Study On The Sealing Effects And Comprehensive Effects Of Widely-used Inert Lost Circulation Materials

Lost circulation is the most common problem which we may encounter during the drilling. It not only delay the time of drilling,extend drilling period,spend a lot of lost circulation material, but also cause a series of accident such as sticking,well spout,collapse. The well will be abandoned if the lost circulation is serious, and causes vast economic loss to drilling engineering. Lost circulation has been the focus of the area of drilling engineering. During the treatment of the lost circulation, lost circulation materials have been the necessary materials. By the low price, extensive source,without toxin and pollution, inert lost circulation materials has been widely used. But the sealing effect isn't ideal as lack of theoretical knowledge of lost circulation and not to judge loss formation, no indicated of inert lost circulation material.In view of the sealing effect isn't ideal of inert lost circulation materials, We select several lost circulation materials which used widely, adapt DS-2 lost circulation simulation equipment as experiment instrument and ordinary mud as medium, brass crack of different widths simulate fractured stratum, stainless bullets pile simulate Opening of stratum, appraised the sealing effects of inert lost circulation materials used alone. Select the materials which have optimal sealing effects for fractured stratum and Opening of stratum. On the basic of the experiment, we study the effects for size of the granule of lost circulation materials and dosage of lost circulation materials, discuss the effects of lost circulation materials which have different size and achieve some worthy Conclusion.On the basis of experiment for inert lost circulation materials which used alone, we appraised the sealing effects of inert lost circulation materials which two materials used together, and compare with the sealing effects of inert lost circulation materials which used alone. And we discussed the impact of lost circulation materials in different conditions for sealing fractured stratum and opening of stratum, analysis mechanism of lost circulation materials in different condition for compound use, the reason of success and fail. On the basis of experiment which two materials used together, we experiment three materials, and appraised the sealing effects, found the most optimal formulation which have optimal sealing effects, and compare with the sealing effects of inert lost circulation materials which used alone and two materials used together. We also analysis the function and factor of inert lost circulation materials in the compound use, discussed the defect of the experiment and pointed the problem which existed.Based on the sealing-simulating experiment of which inert lost circulation materials used alone and two materials used compound, we use the inert lost circulation materials which have the most optimal formulation mixed with water-absorbent lost circulation materials (DIAMOND SEAL polymer, kelp)and DTR separately, appraised the sealing effects with DS-2 lost circulation simulation equipment. We analysis the success and fail reason of the inert lost circulation materials mixed with water-absorbent lost circulation materials (DIAMOND SEAL polymer, kelp)and DTR separately, discussed the function which DIAMOND SEAL polymer, kelp, DTR have. At the same time, we study the factor which DTR impact the mud trait, discussed the defect of the experiment and put forward some advice for the research next.